73 was the first year. Came with the flattops to aid in preventing vapor lock maybe?Plus there might have been some emission ramifications too. It came on when ignition was turn to start only, as I recall. Mine stayed on all the time as the PO had set it up that way. I think the harness is there though if you want to retrofit.
DK

I would have to look through some of the old FSMs to be sure, but I seem to recall posts saying that the 240Z was wired for an electric fuel pump. The 240Z in America did not come with an electric fuel pump, but you might find 73s with them as that was one of the measures taken to reduce vapor lock.

The electric fuel pumps found on the 73 and 74 cars are but one of a series of potential modifications designed to address issues with vapor lock, and/or percolation due to heat soak in the mechanical fuel pump and fuel lines. The first caused a lean condition and the latter caused a rich condition and as well as overfill the float bowl resulting in raw fuel being spilled out into the air cleaner. All bad things. These things were really only an issue with the bulkier and dreaded flat top Hitachi carbs. These have mostly been replaced with the more popular round tops as a quick fix, or to avoid the final mod which consisted of installing a special hood scoop that required cutting holes in the hood. Not a very attractive mode IMHO. Finally, I seem to recall hearing that the wiring for the electric fuel pump may have been present on cars earlier than 73 but I don't know when that started or why it started prior to the 73.

Datsun came out with what they called the V3 kit to "fix" the vapor lock problem on the 73 cars, leading me to believe that the 73's did not come with it or at least didn't until later in the model year. The kit had an 8 blade fan, pump, relays, wiring, and insulation for the fuel lines under the hood. I installed one on the 72 I had many years ago.

Your car didn't come with an electric pump, but was probably wired for it. When you installed the V3 kit, the instruction pointed out where to find the wiring as it was already there. In fact the frame was already tapped for the screws that held the electric fuel pump. You just had to mount the pump, run the lines, plug in the relays and you were good to go.